ABSTRACT Substance use disorders (SUDs), including opioid use disorders, continue to be one of the most serious public health issues in the US,1 leading to negative physical and mental health problems, family disruption, and premature death.2-4 African Americans with drug use histories that are under criminal justice supervision are particularly vulnerable to experiencing the negative consequences associated with SUDs due to higher levels of economic hardship.4 Outpatient treatment delivered in community-based settings is the dominant modality for SUD treatment, typically involving weekly psychosocial counseling sessions in an individual and/or group format.5,6 Longer retention in treatment is associated with better outcomes including reductions in substance use, mental health problems, and societal costs.7-10 Unfortunately, less than half of those individuals who initiate treatment successfully complete it. 6,50-52 African Americans in particular have lower treatment retention and completion rates as compared to Whites,11,12 constituting an ongoing risk for relapse and escalating substance use.6,13,14 One potential way to improve engagement and retention in substance use treatment involves ongoing client and counselor feedback during treatment. The structure of outpatient treatment typically involves intermittent clinical contact between client and counselor, generally on a weekly basis, and often in a group- based format, leaving clinicians with a deficit of information regarding client progress between weekly treatment sessions. Recent addiction research suggests that obtaining information from clients between weekly treatment sessions could provide counselors with valuable and timely data regarding client treatment needs, potentially enhancing their ability to deliver quality care and client-centered treatment, and improving treatment engagement and retention, and perhaps abstinence outcomes.15,16 The Daily Progress System (DPS) is a mobile-friendly, web-based software application designed to improve treatment engagement and retention and reduce therapeutic information deficits. The DPS will provide appointment reminder notifications and collect risk and protective factor information from clients in addiction treatment on a daily basis. Prior to clients? weekly counseling sessions, the DPS will generate a brief, one-page weekly summary report for counselors and clients that will summarize client daily report information, which can be used to improve the delivery of group- and individual-based treatment services. By improving client engagement and retention in treatment, this innovative technology has great potential to reduce health disparities regarding substance use treatment outcomes that affect one of the most vulnerable segments of the population (i.e., African Americans with drug use histories under criminal justice supervision). Given the continued public health crisis of SUDs, including opioid use disorders, technologies to enhance engagement and retention in treatment are urgently needed. If proven efficacious, the DPS could be deployed across the growing national network of outpatient substance use treatment providers, and health care centers that provide substance use treatment, to enhance quality care and improve client outcomes, potentially having high public health impact.